Time calculator



June 12, 1923. 1,458,649 R. N. GARDNER TIME CALCULATOR Filed April 12, 1922 INVENTOR N 72.0fm! 71. 5000 B) 7M4 M ATTORNEYS.

Patented June 12, 1923.

UNITED STATES RICHARD N. GARDNER, OF SAN FRANCISCO, CALIFORNIA.

TIME CALCULATOR.

Application filed April 12, 1922. Serial No. 551,799.

T 0 all whom it may conaern:

Be it known that I, RICHARD N. GARDNER, a citizen of the United States, residing at the city and county of San Francisco and State of California, have invented certain new and useful Improvements in Time .alculators, of which the following is a specification.

My invention relates to the class of sliderule calculators, and is particularly adapted for calculating elapsed time.

The object of my invention is to provide a device for calculating the elapsed time of workmen, between going on and going off duty, and further to calculate the overtime, or time spent on duty over a certain specified length of time, and for which a greater rate of wage is allowed.

My device is particularly well adapted.

for use in calculating-the time of railway workmen, for the reason that such men, particularly those in train and yard service, go on and off duty at odd times, and work for various and unequal lengths of time. In such work, my calculator is of use not only to determine the elapsed time and over-time spent by the workman on duty, for the purpose of calculating his pay therefor, but also to determine the hour at which he shall be relieved from or called for duty after he has worked for the maximum permitted shift or has been off duty for the required length of time. Such calculations, if made by pencil and paper are troublesome and lengthy, especially in the case of railway men whose hours are irregular, and are further subject to error. By the use of my device, however, they may be made instantly and with great accuracy.

An additional feature of my invention is that the total elapsed time and the overtime are taken from the scales as separate figures, although both are determined by one setting of the device, and appear in adjacent positions. This is also of advantage in railway work, for the reason that elapsed,

or straight time and over-time, and the amounts paid therefor, are always kept separate in the compilation of statistics.

It is to be understood, however, that my device is not limited to use in railway work, but may be used for determining the time of employees in an industry or shop, or for calculating the e apsed time between any two known limits for any purpose whatsoever. Moreover, although my invention is herein described and illustrated in its preferredform, it is to be understood that changes may be made in the form and construction of the device within the scope of the claims hereto appended.

My invention will now be fully described with reference to the accompanying drawin wherein-- ig. 1 is a; plan view, broken, of my timeca-lculator, the slides being shown in their fully retracted positions.

Fig. 2 is a similar view showing the elapsed time slide partly extended.

Fig. 3 is a similar view showing both slides partly extended.

Fig. at is a transverse section, taken on the line 44 of Fig. 3, and viewed in the direction of the arrows.

In the drawings, the reference numeral 1 designates the body of my calculator, and is formed after the manner of the wellknown slide-rule, having in its face a groove 2 extending for its full length. Said groove has undercut sides, forming a guide for a slide 3, also extending the full length of the body 1, and capable of sliding in either direction therein. The slide 3 is also provided with an undercutgroove 4, extending for a portion of its length, and in which is mounted a second slide 5. This second slide thus extends from a point somewhat back from the left hand end of the first slide 3 to the right hand end thereof, and is capable of being moved toward the right from its normal position shown in Fig. 1.

The body 1 is provided, along its upper portion adjacent to the upper edge of the slide 3, with a scale 6 having equally spaced graduations representing the hours and minutes of the clock, the smallest graduations preferably representing five minute intervals. This scale extends the entire length of the body 1, and, in the example shown in the drawings, begins with the 12th hour at the left hand end, (which may be taken either as noon or midnight) and runs consecutively to the second 9th hour following, at the right hand end, representing a total time of 21 hours. The length of the body 1, and of the clock scale 6, is immateria They may be longer or shorter, depending upon the class of service for which the device is designed. Similarly, the unitgraduation of said scale 6 may be given any desired value, depending upon the use for which the device is made. The essential EcJlJllZQS of the scale 6, however, are that t must represent time as expressed by the clock, and its graduations must he equally spaced throughout its length. Said scale is suitably marked with the proper o figures, preferably as shown in the drawngs, to enable rapid and accurate reading.

The larger, or full-length slide 3 is also provided with a scalel, whose graduating lines extend from the upper edge or said slide 3 to the upper edge of the smaller slide 5, and correspond, in spacing and unit value, with the unit graduations of the clockscale 6 throughout its entire length. the example shown in the drawings, the unit value of the slide scale 7 istherefore 5 minutes, corresponding to the 5 minute interval between the unit graduations of the clock-scale 6. The graduations of the slide scale 7 are designated by figures placed immediamly to the left of each graduating line in the space between it and the preceding line. Said figures are placed one below the other, for convenience in lettering and reading, and should be read from the top down, the upper one or two figures representing hours and the lower two representing min- 2 Thus the figures 0 in the second 2 space from the right-hand end of the scale 7, in F ig. 1, should be read 20 hours and 55 minutes, Said scale 7, as will be seen, begins with O at the left-hand end of the slide 3, and progresses continuously by 5- minute intervals to 21 hours at the righthand end. In actual practice each graduating line of the scale 7 will be num cred, but, for the sake of clearness the greater part of such numbers have been omitted from the drawings.

The scale 7 may be termed the elapsedtime scale, and its function is to calculate the number of hours and minutes elapsing between two known points of time on the fixed clock-scale 6. For example, it the problem is to determine the time elapsing between 1.55 a. m. and 620 p'. m., the zero mark on the elapsed-time scale 7 is placed. at the mark indicating 1.55 on the clockscale 6, as shown in Fig.2. Then the de sired result, 16 hdurs and 25 minutes, will he found on the elapsed-time scale 7 below the second 6.20 mark on the clock scale 6..

For convenience, I prefer to provide a short additional clock-scale 6', similar to the scale 6, on the lower portion of the body 1 adjacent to the lower edge of the slide 3, said scale 65 beginning with 5 oclock at the left-hand end of said body 1 and running consecutively to 12 oclock, or 7 hours. zero mark 7' is placed on the lower portion of the slide 3 for use with ates.

said scale 6, said zero mark 7 standing 12 on said scale 6' when the zero mark of the main elapsed-time scale 7 stands at 12 on the main clock-scale 6. Thus for initial settings between 5 and 1.2 ocloclr, the slide 3 can be moved to the left and set by means oi the zero mark 7 and the scale 6. This gives a greater range oi calculation, and avoids having to move the slide 3 to the right beyond 5 oclock on the clock scale 6.

The inner and shorter slide 5 is provided with a scale 8, which may be termed the over-time scale, said scale having graduations throughout its length similar to and corresponding with the graduations of the elapsed-time scale 7. The figures designating the values of the graduations of said over-time scale 8 are arranged similarly to those of the scale 7, that is, the figures are placed to the left of the line to which they reteig'and are arranged one below the other, the upper figures representing hours and the lower ones minutes, and they progress (consecutively from left to right. As in the case of the elapsed-time scale 7 previously described, each graduation of the scale 8 should be marl-zed with figures representing its value, but for the sake of clearness the greater portion of these figures have been omitted from the drawings. The unit value of the over-time scale 8, however, depends on the wage rate paid for over-time work in the particular industry for which the scale is made. The ratio between the unit value of the over-time scale 8 and that of the elapsed-time scale 7 is equal to the ration between the increase in the wage rate paid for over-time work and the basic or straight-time wage rate. Thus in the example shown in the drawings, which is designed tor use in calculating the time of men receiving time and one-half or a 50% increase for over-time work, the unit value of the over-time scale 8 is one-half that of the elapsed-time scale 7, or 21} min utes. If the over-time rate were doubletime, or a 100% increase over the straight time rate, the unit value of the over-time scale 8 would be the same as that of the elapsedtime scale 7. It the calculator is to be used in a. factory in which different classes of workmen receive different overtime rates, a different slide 5 must be pro vided for each such rate, it being necessary merely to substitute one side for another when changing from the calculations of one -rate to those of another.

The efiect of this valuation of the overtime scale 8 is to adjust the actual over-time to an apparent figure (expressed in hours and minutes) which can be either added directly to the straight, or elapsed time, or calculated, for determining the wage to he paid, at the straight-time rate. This results in a considerable saving of time and trouble in figuring pav rolls, and decreases the chance of error. or example, if a man Works from 1.55 a. m. to 6.20 p. m. lllS elapsed time is 16 hours and 25 minutes, as shown in Fig. 2and explained above. Reading down on the overtime scale 8 immediately below 16.25 on the elapsed-time scale 7, the time-kee er finds the fi ures 4 hours 121} minutes. e then mere y adds this amount to the elapsed time, giving 20 hours 37% minutes, and multiplies this sum by the straight-time rate to determine the total wagedue the Workman. There is necessary, therefore, only one addition and one multiplication, whereas if the overtime were kept at its actual time value of 8 hours and 25 minutes, the elapsed time (16 hours and 25 minutes) would have to be multiplied by the straight-time rate, and the over-time (8 hours and 25 minutes) by the excess overtime rate (or 50% of the straight-time rate), and the two results added together to give the total wage, thus involving two multiplications, at difi'erent rates, and one addition. This elimination of one step in the calculation results in a considerable saving in time, as well as increased accuracy, Where large numbers of workmen are involved, and more especially when pay rolls are figured. monthly or at similar intervals.

It has been assumed in the above that the overtime is to be paid only after the expiration of eight hours Work, and in such cases the zero point on the overtime scale 8 falls beneath the 8 hour point on the elapsedtime scale 7, as shown in Figs. 1 and 2. If, however, over-time is to be paid after any greater length of time, the over-time slide 5 is moved to the right until the zero point of the over-time scale 8 falls under the point on the elapsed-time scale 7 at which such overtime begins. Thus, for example, if overtime is to be paid after 9 hours work, the slide 5 is moved to the position shown in Fig. 3, so that the zero point of the overtime scale falls under the 9 hour line of the elapsed-time scale 7. Assuming the elapsedtime to be 18 hours and 25 minutes, as before, the apparent overtime value is now 3- hours and {12% minutes, giving an apparent for at the straight-time rate.

In the typical form of my invention herewith illustrated the left-hand limit of movement of the over-time slide 5 is fixed at the 8 hour line on the elapsed-time scale 7, for the reason that over-time is usually figured after eight hours, and it is convenient to push said slide 5 to its stop when figuring the greatest number of calculations. However, the groove l off the over-time slide 5 may be of such a length that said slide will stop at any other desired point, depending upon the working conditions in the industry for which the device is intended.

It should be noted that my calculator does not combine the elapsed time and the overtime in one result, but gives them separately, the over-time being expressed in terms of the straight-time rate. This is of. particular advantage in the compilation of statistics, and especially in railway work, for the reason that elapsed-time and over-time are always kept separate in such statistics.

Another example of the uses of my calculator is in determining the hour at which a man may go on or oil duty, after fixed periods of rest in work. For instance, a certain train-man has been on duty continuously since 1.55 a. m. Regulations provide that he must be relieved after 16 hours of duty. Setting the zero point of the scale 7 at 1.55 on the clock-scale 6, as in Fig. 2, the hour at which this man must be relieved, viz. 5.55 p. m. is found on said scale 6 above the 16 hour line on the scale 7. i

I claim A slide rule calculator comprising a body member having a fixed scale; a movable slide having a scale for indicating the arithmetical difierence between any two given points on the fixed scale; and a second movable slide, said second slide having a scale for indicating in terms of a predetermined coefficient the arithmetical difference between any two given points on the scale of the first slide.

In testimony whereof I have signed my name to this specification.

RICHARD N. GARDNER.

total of 20 hours and 7% minutes to be paid 

